How does wheelcollider mass factor into rigidbody mass?

Let’s say I have a car with a rigidbody mass of 1500 and four wheelcolliders with a mass of 20 each. Is the mass then, of the entire car, 1580, or is it still 1500, but the car without the wheelcolliders is 1420?

Overall mass of rigidbody remains same as 1500 and your wheelcolliders has 20 for each.
Car mass (1500) = wheelcolliders (80) + otherbody (1420)